Conventionally in the manufacture of an electronic watch, an integrated circuit chip (hereinafter referred as an IC chip) is mounted on a lead frame such as KOVAR (trademark) and is then molded in epoxy resin. Thereafter the molded IC chip is soldered onto a substrate which is then secured on a metal base or frame of the electronic watch. This method, however, is disadvantageous with respect to cost since the IC chip is soldered onto the substrate after molding through a separate process. It is also disadvantageous with respect to space since the construction does not lend itself to making a small wrist watch.
In another method of assembly, a substrate for an electronic timepiece is made by the following process: An IC chip is mounted in a recess of a substrate of insulating material having thereon metal foil in a pattern to define circuitry. The substrate with the IC chip thereon is then molded into a frame by a transfer molding process. As the molding cycle of transfer molding is long and the productivity is low, the cost of manufacture by this process is correspondingly high. Moreover the cost is further increased by the need of using a metallic mold.